We describe the radiometric performance and ground calibration results of the JUpiter ICy moons Explorer Ultraviolet Spectrograph (JUICE-UVS) instrument. JUICE-UVS is a modest power (8 W) ultraviolet spectrograph that is the fifth in a series of Alice/UVS instruments built by Southwest Research Institute. JUICE-UVS covers a 50-204 nm bandpass with 0.4 nm spectral resolution over a 7.5° field of view with better than 0.3° spatial resolution. JUICE-UVS also features three different observing modes to allow higher-than-nominal spatial resolution observing as well as solar occultations in the Jupiter system. JUICE-UVS meets all performance requirements with margin, and is the first planetary UV spectrograph to feature a microchannel plate detector with an atomic layer deposition (ALD) coating to minimize in-flight gain loss due to accumulated fluence. JUICE-UVS also features both a time-tagged pixel list observing mode and a programmable histogram mode to maximize observational flexibility and data management. During the main JUICE mission, JUICE-UVS will explore the atmospheres and surfaces of the Galilean satellites, examine the dynamics of Jupiter’s upper atmosphere from pole to equator, and investigate the Jupiter-Io connection through observations of the Io torus.